Rinse added fabric softener compositions are well known, however one of the problems associated with fabric softening compositions is that the viscosities of the formulations are difficult to control.
EP 0 358 749 (Unilever) discloses an aqueous fabric conditioning composition comprising a cationic fabric softener and a polymeric thickening materials such as nonionic polymers based on polyoxyalkylene or polvinylalcohol hydrophilic backbones to which a small number of alkyl groups have been attached. The application teaches that it is preferred if the polymeric thickening materials have a high molecular weight.
Hydrophobically modified nonionic cellulose ethers are used to thicken aqueous fabric softening compositions in EP 0 331 237 (Unilever).
We have found that it is possible to control the viscosity of a fabric conditioning composition with a greater degree of control than previously thought possible. We have also found that by including certain polymers, rinse conditioners can be prepared using conventional processes without needing a separate processing step for the addition of the viscosity control agent.